Centrifugal pump



May 28, 1963 J. R. NAHRGANG CENTRIFUGAL PUMP jdmesfflfagJ g a g,

ATTORNEY 3,091,183 CENTRIFUGAL PUMP James R. Nahrgang, Grand Island, N.Y. (4445 Central Ave, Indianapolis 5, Ind.) Filed Feb. 23, 1960, Ser. No. 10,303 6 Claims. (Cl. 103-113) This invention relates to centrifugal pumps and more particularly to improvements in the vertical axis type of centrifugal pumps.

Prior centrifugal pumps tend to have a characteristic known as air binding resulting in slippage between the rotor and the material being pumped. When air binding and the resultant slippage occurs the maximum pumping efficiency of such pumps is appreciably reduced.

An object of the present invention is to provide an imroved vertical axis type of centrifugal pump wherein liquid material is pumped in a manner to overcome or at least materially reduce air binding and the resultant slippage which reduces the efliciency of such pumps.

Another object is to provide an improved vertical axis type of centrifugal pump which will efiiciently pump liquids containing more or less fibrous, abrasive or other materials or liquids substantially free of any such materials, for long periods of time without excessive wear of the pump parts.

Another object is to provide an improved vertical axis type of centrifugal pump with an improved rotor formed, arranged and rotatably mounted therein to pump liquids and liquid materials in a manner which tends to release entrained air or gas into a chamber of the pump from which it can be readily discharged when desired.

Another object is to provide an improved vertical axis type of centrifugal pump having a small number of simply for-med component parts which require a minimum of machining and which, being easy to assemble, allows the pump to be manufactured and sold at a reasonable price.

These and other objects of the present invention will appear from a perusal of the following detailed description and the drawing. However it should be understood that the description and drawing are intended to exemplify the principles of the invention and that various modifications of the form and arrangement of the component parts of the pump may be made within the scope of the appended claims.

In the drawing:

FIGURE 1 is a top plan view of an improved vertical axis type of centrifugal pump constructed in accordance with the principles of the present invention.

FIGURE 2 is a vertical sectional view taken about on the line 22 of FIGURE 1 and showing certain parts in elevation.

FIGURE 3 is a horizontal sectional view taken about on the line 33 of FIGURE 2, and

FIGURE 4 is an enlarged fragmentary vertical sectional view showing a modified form of pumping rotor. Referring now to the drawings wherein like reference numerals denote like parts, a pump constructed in accordance with the principles of the present invention is generally indicated by the numeral and includes a suitable motor 11 spaced from a pump housing 12 by an annular spacer 13 formed with hand holes 14 providing access thereto. A plate 15, being formed with a central boss 16 which is axially bored to receive a bearing 17 and a shaft seal 18, is secured between the flanged lower end of the spacer 13 and the flanged upper end of the annular wall 19 of an inlet chamber 20 by any suitable fastening means. The wall 19 is formed with an inlet opening 21 and at its juncture with the smaller end of a frusto conically shaped annular wall 22 of the pump housing 12 3,091,183 Patented May 28, 1963 is formed with an inwardly extending wall 23 having a central opening 24.

The wall 23 thus divides the housing but its central opening 24 provides communication between the inlet chamber 20 and a frusto-conically shaped rotor chamber 25 formed by the walls 22 and 23. The wall 23 is preferably inclined toward the rotor chamber and the area of its central opening 24 approximates the area of the inlet opening 21, whereby the flow of liquid material by gravity through the inlet opening 21, the chamber 20 and the central opening 24 into the rotor chamber 25 is unrestricted.

The open larger end of the chamber 25 is formed with an outwardly and downwardly extending curved annular wall 26 having a circumscribing flange 27 so that the wall 25 together with a like shaped and flanged annular wall 23 formed on the periphery of a closure plate 29 provides an enlarged annular chamber 30 in open communication with the rotor chamber 25.

The walls 25 and 28 are each formed with complementary tangential or volute shaped portions 26 and 28' which together provide a tangential or volute shaped outlet 31 from the chamber 30. The abutting flanged edges of the walls 26, 28, '26 and 28' may be secured together by any suitable means but are preferably secured together by bolts 32 so that the closure plate 29 may be readily assembled and secured in place to complete the pump housing and readily removed to provide access to the chambers 30 and 25.

The spacer 13, the bearing 17, the seal 18, the inlet chamber 20, the rotor chamber 25 and the chamber 30 are concentric with the axis of the drive shaft of the motor 11. A solid rotor shaft 35 rotatably mounted in the bearing 17 has its upper end drivingly connected to the motor drive shaft by a suitable coupling 36.

The solid shaft 35 extends through and is engaged by the shaft seal 18 in the usual manner to prevent leakage of liquid from the inlet chamber 20. The lower end portion of shaft 35 is drivingly connected, as by a threaded connection 37, directly to the center of a substantially flat circular bottom wall 41 of a frusto-conically shaped rotor shell 40. The lower end portion of the shaft 35 immediately above the driving connection 37 is enlarged and bell shaped as at 38 for purposes to be hereinafter de scribed.

The rotor shell 40, preferably although not necessarily, is of a unitary form in which the bottom wall 41 is integated with and at the lower end of a frusto-conically shaped annular side wall 42. The rotor shell 40 is reinforced by an integral depending boss 43 at the center of the wall 41, and the wall 42 above its juncture with the bottom wall 41 is formed with a plurality of evenly spaced radially or otherwise disposed discharge apertures 44. The walls 41 and 42 at their juncture are formed with a plurality of spaced inwardly directed small substantially triangularly shaped radially or otherwise disposed reinforcing gussets 45, which are spaced from said apertures. 44 (FIGURE 3).

The rotor shell 40, being rotatably supported by the solid shaft 35 in concentric relation thereto, is formed and located so that the outer surface of its wall 42 is in evenly spaced relation to the inner surface of the wall 22 and so that the smaller end of rotor shell 40 terminates intermediate the top and bottom of the Wall 22. The larger end of rotor shell 40 extends into the chamber 30 and terminates in spaced relation to the closure plate 29, whereby the discharge apertures 44 lie about midway between the walls 26 and 28 of the chamber 30.

Referring to FIGURE 2 it will be seen that during operation of the pump a central column of liquid or slurry containing more or less entrained air or gases, in flowing downwardly around the shaft 35, will flow over and be smoothly directed outwardly by the bell-shaped enlargement 38 onto the contiguous surface of the wall 41 in the manner indicated by arrows. Upon contacting the rapidly rotating plate 41 the liquid or slurry will be rotated'thereby and forced outwardly across its surface by centrifugal force at progressively increasing speeds and force during its movement over diametrically larger portions of the Wall 41. The progressing increase of the speed and centrifugal force of the liquid or slurry as it moves across the wall 41 tends to release entrained air or gases. The released air or gases may be allowed to accumulate in the chamber 'until the pressure therein exceeds atmospheric pressure whereupon they may escape through a suitable valve located in the wall 22 and indicated by the numeral 46 or they may be continuously or intermittently removed from the chamber 20 by a conduit 47 indicated by broken lines in FIGURE 2 and connected to a suitable evacuating pump (not shown).

Due to the centrifugal force imparted to the liquid or slurry during its outward movement across the wall 7 41 a predetermined portion of the liquid or slurry is forced through the apertures 44- into and through the chamber and through its outlet 31 and another portion of the liquid or slurry is forced up, held against and rotates with the wall 42, thereby forming an annular rotating mass of liquid or slurry shaped substantially as shown in broken lines in FIGURE 2. The volume of the annular shaped rotating mass of liquid or slurry may vary slightly during operation of the pump due to several causes. However its volume is always suflicient to cover the reinforcing gussets 45, which also serve as liquid propelling vanes, and which because they resist relative movement between the rotating annular mass of liquid or slurry and the walls 41 and 42 prevent wear therebetween and turbulence in said mass whichrnay cause reentrainment of air or gases therein. It will be noted that liquid or slurry flowing into the rotor shell wets the entire exposed top surface of the wall 41 and an adjacent inner portion of the wall 42, and that, notwithstanding the flow may be continuous, the wearing efiect of any wear producing material in the liquid or slurry on the wetted surfaces of the rotor is very low.

In order to further increase the pumping efficiency of the rotor in forcing liquid or slurry, around and through the stationary chamber 30 and from its outlet 31, the outer peripheral surface portion of the larger end of the Wall 42 is formed, as shown in FIGURES 2 and 3; with a plurality of spaced radially extending or otherwise disposed small external vanes 48. The vanes 48, being spaced to avoid interference with the discharge ports 44 (FIGURE 3) and being shaped to extend into the chamber 30 in spaced relation to its Walls and to extend above and below the discharge apertures 44 (FIG- URE 2), serve to rotate the liquid discharged into the chamber 30 at the same speed as that of the rotor, thereby materially reducing the tendency of the stationary walls of the chamber to slow down the forcible flow of liquid around the chamber and through its outlet, whereby the pumping pressure of the pump is maintained.

As shown in FIGURE 4 a plate 49' is secured in substantially flush relation to the depending boss 43 of the rotor shell 40 and to the larger end of its wall 42, to close the space therebetween, and thereby reduce any tendency of the rotor to create turbulence in the liquid being pumped.

I claim: e

1. A liquid transferring apparatus for conveying a liquid which includesentrained gases and for separating said gases from said liquid comprising a housing, an annular rotor shell in saidhousing constructed and arranged to receive a liquid having entrained gases, said annular rotor shell having an upwardly converging wall and a substantially smooth circular bottom wall, motor means connected to' and rotating said rotor shell, liquid inlet means communicating with said rotor shell directing liquid to flow toward the center of said substantially smooth circular bottom wall and to enter liquid in said rotor shell in the vicinity of the center thereof to thereby cause liquid from said liquid inlet means to enter said liquid in said rotor shell with a minimum of turbulence, liquid oulets in said side wall proximate said substantially smooth bottom wall permitting passage of liquids from said rotor shell, said liquid flowing outwardly from the center of said bottom wall toward said liquid outlets and toward said converging wall across said substantially smooth bottom wall with increasing linear velocity as a result of the rotation of said rotor shell, the rate of liquid being supplied to said rotor shell through said liquid inlet means maintaining said rotor shell filled to a sulficient depth so that the upper level of liquid in said rotor shell is above said liquid outlets and the rate of rotation of said annular rotor shell being of a magnitude to cause the velocity of outward liquid flow in said rotor shell to cause said entrained gases to be released from said liquid in said rotor shell while the contact between said liquid with said upwardly converging side wall minimizes turbulence of said liquid to thereby prevent re-entrain ment of gases into said liquid in said rotor shell, and vent means permitting said released gases to escape from said rotor shell.

2. A liquid transferring apparatus as set forth in claim 1 wherein a vertically disposed shaft is connected to the center of said substantially smooth bottom wall and wherein said motor means drives both said shaft and said annular rotor shell because of the connection between said motor means, vertically disposed shaft and the bottom wall of said rotor shell, and wherein a portion of said shaft is located proximate said liquid inlet, whereby the liquid flow through said liquid inlet flows down said shaft into the liquid on said bottom wall thereby minimizing turbulence between said liquid flowing down said shaft and the liquid in said rotor shell in the area at the bottom of said shaft and said bottom wall.

3. A liquid transferring apparatus as set forth in claim 7 1 wherein said liquid outlets in said side wall are so located that the liquid flow through said outlets is de rived from the liquid located between the portions of said liquid in contact with said bottom wall and said wall of said rotor shell, thereby substantially preventing relative movement between the surfaces of said liquid in contact with said annular rotor shell to thereby prevent wear of said annular rotor shell resulting from the impifigement of abrasive particles thereon. i

4. A liquid transferring apparatus for conveying a liquid which includes entrained gases and for separating said gases from said liquid comprising a housing, an annular rotor shell in said housing, said' annular rotor shell having an upwardly converging wall and an open top and a substantially smooth circular bottom wall, motor means connected to and rotating said rotor shell, liquid inlet means communicating with said rotor shell for permitting liquids to flow by gravity toward the centerof said substantially smooth circular bottom wall, liquid outlets in said side wall proximate said substantially smooth bottom wall permitting passage of liquids from said rotor shell, said liquid flowing outwardly from the center of said bottom wall toward said liquid outlets across said substantially smooth bottom wall with increasing linear velocity as a result of the rotation of said rotor shell, the

rate of liquid being supplied to said rotor shell maintaining said rotor shell filled'to' a sufficient depth so that the upper level of liquid in said rotor shell is above said liquid outlets and the-rate of rotation of said annular rotor shell being of a magnitude to cause the velocity of outward liquid flow in said rotor shell to, cause said entrained gases to be released fromsaid liquid" in said rotor shell while the contact between the upper level of said liquid with said upwardly converging side wall minimizes turbulence of said liquid to thereby prevent reentrainment of gases into said liquid in said rotor shell,

and vent means permitting said released gases to escape from said rotor shell.

5. A liquid transferring apparatus as set forth in claim 4 wherein a vertically disposed shaft is connected to the center of said substantially smooth bottom wall and wherein said motor means drives both said shaft and said annular rotor shell because of the connection between said motor means, vertically disposed shaft and the bottom wall of said rotor shell, and wherein a portion of said shaft is located proximate said liquid inlet, whereby the liquid flow through said liquid inlet flows down said shaft into the liquid on said bottom wall thereby minimizing turbulence between said liquid flowing down said shaft and the liquid in said rotor shell in the area at the bottom of said shaft and said bottom wall.

6. A liquid transferring apparatus for conveying a liquid which includes entrained gases and for separating said gases from said liquid comprising a housing, an annular rotor shell in said housing constructed and arranged to receive a liquid having entrained gases, said annular rotor shell having an upwardly converging wall and a substantially smooth circular bottom wall, motor means connected to and rotating said rotor shell, liquid inlet means communicating with said rotor shell directing liquid to flow toward the center of said substantially smooth circular bottom wall and to enter liquid in said rotor shell in the vicinity of the center thereof to thereby cause liquid from said liquid inlet means to enter said liquid in said rotor shell with a minimum of turbulence, liquid outlets in said rotor shell proximate the junction of said side wall and said bottom wall permitting passage of liquids from said rotor shell, said liquid flowing outwardly from the center of said bottom wall toward said liquid outlets and toward said converging wall across said substantially smooth bottom Wall with increasing linear velocity as a result of the rotation of said rotor shell, the rate of liquid being supplied to said rotor shell through said liquid inlet means maintaining said rotor shell filled to a suflicient depth so that the upper level of liquid in said rotor shell is above said liquid outlets and the rate of rotation of said annular rotor shell being of a magnitude to cause the velocity of outward liquid flow in said rotor shell to cause said entrained gases to be released from said liquid in said rotor shell while the contact between said liquid with said upwardly converging wall minimizes turbulence of said liquid to thereby prevent reentrainment of gases into said liquid in said rotor shell, and vent means permitting said released gases to escape from said rotor shell.

References Cited in the file of this patent UNITED STATES PATENTS 38,553 Brazelton May 19, 1863 464,716 Robinson Dec. 8, 1891 2,237,027 Dorer Apr. 1, 1941 2,376,071 Miess May 15, 1945 2,419,905 Miess Apr. 29, 1947 2,747,514 Edwards May 29, 1956 2,788,171 Kulow Apr. 9, 1957 FOREIGN PATENTS 16,500 Denmark Sept. 26, 1912 19,030 Great Britain Sept. 6, 1898 515,749 Italy Feb. 16, 1955 

1. A LIQUID TRANSFERRING APPARATUS FOR CONVEYING A LIQUID WHICH INCLUDES ENTRAINED GASES AND FOR SEPARATING SAID GASES FROM SAID LIQUID COMPRISING A HOUSING, AN ANNULAR ROTOR SHELL IN SAID HOUSING CONSTRUCTED AND ARRANGED TO RECEIVE A LIQUID HAVING ENTRAINED GASES, SAID ANNULAR ROTOR SHELL HAVING AN UPWARDLY CONVERGING WALL AND A SUBSTANTIALLY SMOOTH CIRCULAR BOTTOM WALL, MOTOR MEANS CONNECTED TO AND ROTATING SAID ROTOR SHELL, LIQUID INLET MEANS COMMUNICATING WITH SAID ROTOR SHELL DIRECTING LIQUID TO FLOW TOWARD THE CENTER OF SAID SUBSTANTIALLY SMOOTH CIRCULAR BOTTOM WALL AND TO ENTER LIQUID IN SAID ROTOR SHELL IN THE VICINITY OF THE CENTER THEREOF TO THEREBY CAUSE LIQUID FROM SAID LIQUID INLET MEANS TO ENTER SAID LIQUID IN SAID ROTOR SHELL WITH A MINIMUM OF TURBULENCE, LIQUID OUTLETS IN SAID SIDE WALL PROXIMATE SAID SUBSTANTIALLY SMOOTH BOTTOM WALL PERMITTING PASSAGE OF LIQUIDS FROM SAID ROTOR SHELL, SAID LIQUID FLOWING OUTWARDLY FROM THE CENTER OF SAID BOTTOM WALL TOWARD SAID LIQUID OUTLETS AND TOWARD SAID CONVERGING WALL ACROSS SAID SUBSTANTIALLY SMOOTH BOTTOM WALL WITH INCREASING LINEAR VELOCITY AS A RESULT OF THE ROTATION OF SAID ROTOR SHELL, THE RATE OF LIQUID BEING SUPPLIED TO SAID ROTOR SHELL THROUGH SAID LIQUID INLET MEANS MAINTAINING SAID ROTOR SHELL FILLED TO A SUFFICIENT DEPTH SO THAT THE UPPER LEVEL OF LIQUID IN SAID ROTOR SHELL IS ABOVE SAID LIQUID OUTLETS AND THE RATE OF ROTATION OF SAID ANNULAR ROTOR SHELL BEING OF A MAGNITUDE TO CAUSE THE VELOCITY OF OUTWARD LIQUID FLOW IN SAID ROTOR SHELL TO CAUSE SAID ENTRAINED GASES TO BE RELEASED FROM SAID LIQUID IN SAID ROTOR SHELL WHILE THE CONTACT BETWEEN SAID LIQUID WITH SAID UPWARDLY CONVERGING SIDE WALL MINIMIZES TURBULENCE OF SAID LIQUID TO THEREBY PREVENT RE-ENTRAINMENT OF GASES INTO SAID LIQUID IN SAID ROTOR SHELL, AND VENT MEANS PERMITTING SAID RELEASED GASES TO ESCAPE FROM SAID ROTOR SHELL. 